Hem former and sewing apparatus

Abstract

An air assisted hem former for folding a margin of a foldable material which uses at least one stream of air to urge margin material through a folded cavity. The folded cavity and airflow moves the margin toward a sewing needle, directs the margin material to a proper stitching position and maintain the stitching position until the needle has stitched the hem. Two similarly formed hem formers can be mounted on opposing sides of a sewing needle to urge, direct and maintain the margin material prior to stitching of a hem.

What is claimed is: 
     
       1. An air-enhanced hem former for folding a margin of a foldable material to be stitched, comprising: a first cavity having first and second legs and a bottom joining the legs, the cavity sized to allow air to carry the margin through the cavity, at least one outlet opening into the first leg and directed toward the bottom to introduce an airstream into the cavity, the outlet opening being located along the first leg and before the bottom.   
     
     
       2. The hem former as defined in claim 1, wherein the bottom is curved. 
     
     
       3. The hem former as defined in claim 2, wherein the bottom is generally U-shaped. 
     
     
       4. The hem former as defined in claim 1, wherein the first leg is generally linear and extends along a longitudinal axis. 
     
     
       5. The hem former as defined in claim 1, wherein the second leg is generally linear and extends parallel to the first leg and spaced apart from the first leg by the bottom. 
     
     
       6. The hem former as defined in claim 1, further comprising, a second cavity having first and second legs and a bottom joining the legs, the second cavity sized to allow the airstream to carry the margin through the second cavity, at least one outlet opening into the first leg of the second cavity and directed toward the bottom of the second cavity to introduce an airstream into the second cavity, the outlet being located along the first leg and before the bottom of the second cavity, the first and second cavities being aligned so a margin can be inserted through the first and second cavities, the first and second cavities being spaced apart a distance sufficient to allow a needle to sew the margin between the cavities. 
     
     
       7. The hem former as defined in claim 6, wherein the outlet opens into the cavity within the first 2/3 of the length of the first leg. 
     
     
       8. The hem former as defined in claim 7, wherein the outlet port is orientated at an angle of about 20°-60° relative to a longitudinal axis of the first leg and in a direction toward a longitudinal axis of the second leg. 
     
     
       9. The hem former as defined in claim 1, wherein the second leg terminates in a blind end. 
     
     
       10. The hem former as defined in claim 6, wherein the second leg terminates in a blind end. 
     
     
       11. The hem former as defined in claim 6, wherein at least one of the first and second cavities is formed by a block having a slot in one side terminating interior to the block, and a tongue inserted into the slot to form the legs, the tongue having a distal end that terminates before contacting the interior end of the slot in the block to define the bottom of the cavity. 
     
     
       12. The hem former as defined in claim 1, wherein the outlet opens into the cavity within the first 2/3 of the length of the first leg. 
     
     
       13. The hem former as defined in claim 12, wherein each outlet port is tapered to disperse the airstream. 
     
     
       14. The hem former as in claim 12, wherein each outlet port is tapered to concentrate the airstream. 
     
     
       15. The hem former as defined in claim 12, wherein the outlet port is orientated at an angle of about 20°-60° relative to a longitudinal axis of the first leg and in a direction toward a longitudinal axis of the second leg. 
     
     
       16. An air-assisted sewing apparatus for folding a margin of a foldable material to be stitched, comprising: a first passageway formed by a first and second generally parallel legs joined by a bottom, the first leg having an end opposite the bottom that forms an opening into which the margin is introduced to the passageway, an outlet in fluid communication with an air source and orientated to introduce an airstream into the first leg directed toward the bottom, the size of the first passageway and the airstream cooperating to move the margin through the passageway and into the second leg;   a second passageway constructed as the first passageway, the second passageway being generally parallel to and separated from the first passageway a distance sufficient to allow a needle to stitch the margin between the passageways.   
     
     
       17. The hem former as defined in claim 16, wherein the cavity is generally U-shaped. 
     
     
       18. The hem former as defined in claim 16, wherein the outlet is located between about 1/3 and 2/3 the length of the first leg. 
     
     
       19. The hem former as defined in claim 16, wherein the outlet is orientated at an angle of about 20°-60° relative to a longitudinal axis of the first leg and in a direction toward a longitudinal axis of the second leg. 
     
     
       20. The hem former as defined in claim 16, wherein the opening is enlarged a distance sufficient to facilitate introduction of the margin into the cavity and the outlet is not located in the enlarged portion. 
     
     
       21. The hem former as defined in claim 20, wherein the outlet is orientated at an angle of about 20°-60° relative to a longitudinal axis of the first leg and in a direction toward a longitudinal axis of the second leg. 
     
     
       22. A sewing apparatus for folding a margin of a foldable material to be stitched, comprising: a first cavity having a U-shaped portion formed by a first and second generally parallel legs joined by a curved bottom, the first leg having an end opposite the bottom that forms an opening into which the margin is introduced to the cavity; and   first airflow means in fluid communication with the first leg for moving the margin through the cavity into the second leg.   
     
     
       23. A sewing apparatus as defined in claim 22, further comprising: a second cavity having a U-shaped portion formed by a first and second generally parallel legs joined by a curved bottom, the first leg of the second cavity having an end opposite the bottom that forms an opening into which the margin is introduced to the second cavity; and   second airflow means in fluid communication with the first leg of the second cavity for moving the margin through the second cavity to an end of the second leg of the second cavity, the second cavity being aligned with the first cavity and separated from the first cavity a distance sufficient to allow a needle to stitch the margin between the cavity.   
     
     
       24. The hem former as defined in claim 23, wherein the outlet is orientated at an angle of about 20°-60° relative to a longitudinal axis of the first leg and in a direction toward a longitudinal axis of the second leg. 
     
     
       25. A method for folding a margin of a foldable material to be stitched, comprising the steps of: introducing the margin into a first, generally U-shaped cavity having first and second legs and a bottom joining the legs, sizing the cavity to allow air to carry the margin through the cavity passing air through at least one outlet opening into the first leg and directed toward the bottom to form an airstream in the cavity, locating the outlet along the first leg and before the bottom, the airstream moving the margin through the cavity and into the second leg opposite the bottom to forms folded margin.   
     
     
       26. A method as defined in claim 25, comprising the further step of introducing the airstream into the cavity at an angle of about 20°-60° relative to a longitudinal axis of the first leg and in a direction toward a longitudinal axis of the second leg. 
     
     
       27. A method as defined in claim 25, comprising the further steps of: introducing the margin into a second, generally U-shaped cavity having first and second legs and a bottom joining the legs, sizing the second cavity to allow air to carry the margin through the second cavity, passing air through at least one outlet opening into the first leg of the second cavity and directed toward the bottom to form an airstream in the second cavity, locating the outlet in the second cavity along the first leg and before the bottom of the second cavity, the airstream moving the margin through the cavity and into the second leg opposite the bottom to form the folded margin, spacing the first and second cavities apart a distance sufficient to stitch the margin between the cavities, and stitching the margin.   
     
     
       28. A method as defined in claim 27, comprising the further step of placing the outlet to introduce air into the cavity within the first 2/3 of the length of the first leg. 
     
     
       29. A method as defined in claim 27, comprising the further step of placing the outlet to introduce air into the cavity within the first 2/3 of the length of the first leg. 
     
     
       30. A method as defined in claim 27, comprising the further step of placing the outlet to introduce air into the first cavity within the first 2/3 of the length of the first leg of the first cavity and to introduce air into the second cavity within the first 2/3 of the length of the first leg of the second cavity. 
     
     
       31. A method as defined in claim 27, comprising the further step of introducing the airstream into the first and second cavities at an angle of about 20°-60° relative to a longitudinal axis of the first leg of each cavity and in a direction toward a longitudinal axis of the second leg of each cavity. 
     
     
       32. A method as defined in claim 27, wherein the cavity is formed by placing a tongue into a cavity in a block to define the U-shaped cavity, and comprising the further step of moving one or both of the tongue and block to vary the cavity to allow movement of the margin. 
     
     
       33. A method for positioning a margin of a foldable material to be stitched by passing the material through a U-shaped cavity having first and second legs joined by a bottom, the first leg having an opening for introduction of the margin and the second leg having an end to limit movement of the margin, comprising the steps of: introducing a first air stream adjacent the opening in the first leg and directed toward the bottom;   introducing the margin into the cavity a distance sufficient to engage the first air stream; and   moving the margin by the air stream to the end of the second leg.   
     
     
       34. A sewing apparatus as defined in claim 33, further comprising the step of sewing the margin. 
     
     
       35. A method as defined in claim 33, comprising the further step of introducing air into the cavity within the first 2/3 of the length of the first leg. 
     
     
       36. A method as defined in claim 33, comprising the further step of introducing the airstream into the cavity at an angle of about 20°-60° relative to a longitudinal axis of the first leg and in a direction toward a longitudinal axis of the second leg. 
     
     
       37. A method as defined in claim 33, wherein the cavity is formed by placing a tongue into a passageway in a block to define the U-shaped cavity, and comprising the further step of moving one or both of the tongue and block to vary the cavity to allow movement of the margin.